\begin{figure}[H]
  \centering
  \includegraphics[scale=.8]{picture/show_1.png}
\end{figure}
\begin{figure}[H]
  \centering
  \includegraphics[scale=.8]{picture/show_2.png}
\end{figure}
\begin{figure}[H]
  \centering
  \includegraphics[scale=.8]{picture/show_3.png}
\end{figure}
\begin{figure}[H]
  \centering
  \includegraphics[scale=.8]{picture/show_4.png}
\end{figure}                    %此处省去5.png 6.png

\begin{flushright}
  \hyperref[content]{回到目录}
\end{flushright}